Shelf system



FIG. 1 is a front perspective view of a shelf system of the present invention with broken lines showing a wall mount to which the shelf system can be coupled and a shelf which can be used with the shelf system, the broken lines forming no part of the claimed design;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a rear elevation view thereof;

FIG. 4 is a left side elevation view thereof;

FIG. 5 is a right side elevation view thereof.

FIG. 6 is a top elevation view thereof; and,

FIG. 7 is a bottom elevation view thereof. 

The ornamental design for a shelf system, as shown and described. 